# US 6,271,557 B1 · Center node for deep trench capacitors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,271,557 B1 - Document ID: US6271557B1 - Status: Granted - Kind: B1 - Application number: 09/412,481 - Filed: 1999-10-05 - Granted: 2001-08-07 - Earliest claimed: 1999-10-05 - Assignees: Infineon Technologies AG - Inventors: Ulrich Zimmermann; Thomas Achammer - Web page: https://patentgrep.com/patent/US6271557B1 ## CPC - H10B 12/37: {the capacitor being at least partially in a trench in the substrate} - H10B 12/00: Dynamic random access memory [DRAM] devices - H10B 12/373: {the capacitor extending under or around the transistor} - H10B: ELECTRONIC MEMORY DEVICES ## Abstract A trench capacitor cell, in accordance with the present invention, includes a trench having an outer electrode formed in a substrate adjacent to the trench. A storage node is formed in the trench and capacitively coupled to the outer electrode. A center node is capacitively coupled to the storage node, and the storage node surrounds the center node within the trench. The center node includes a portion extending from the trench for connecting to a potential to provide charge retention in the storage node during operation. ## Claims ### Claim 1 A trench capacitor cell comprising: a trench having an outer electrode formed in a substrate adjacent to the trench; a storage node formed in the trench and capacitively coupled to the outer electrode; a transfer transistor coupled to the storage node for charging and discharging the trench capacitor; a center node capacitively coupled to the storage node, the storage node surrounding the center node within the trench, the center node including a portion extending from the trench for connecting to a potential to provide charge retention in the storage node during operation. ### Claim 2 (depends on 1) The trench capacitor cell as recited in claim 1, wherein the potential is a constant potential. ### Claim 3 (depends on 1) The trench capacitor cell as recited in claim 1, wherein the portion extending from the trench includes a connection to a wordline. ### Claim 4 (depends on 3) The trench capacitor cell as recited in claim 3, wherein the wordline is an active wordline for the trench capacitor cell. ### Claim 5 (depends on 3) The trench capacitor cell as recited in claim 3, wherein the wordline is a passing wordline. ### Claim 6 (depends on 1) The trench capacitor cell as recited in claim 1, wherein the center node to the storage node capacitance is between about 0.5 fF to about 30 fF. ### Claim 7 (depends on 1) The trench capacitor cell as recited in claim 1, wherein the center node to the storage node capacitance is about 5 fF. ### Claim 8 (depends on 1) The trench capacitor cell as recited in claim 1, wherein the potential is controlled by a control circuit coupled to the center node for adjusting the potential to maintain charge retention in the storage node. ### Claim 9 (depends on 8) The trench capacitor cell as recited in claim 8, wherein the control circuit varies the potential to the center node in accordance with operations performed on the trench capacitor cell. ### Claim 10 A trench capacitor cell comprising: a trench having an outer electrode formed in a substrate adjacent to the trench; a storage node formed in the trench and capacitively coupled to the outer electrode, the storage node being connected to a transfer transistor which enables the storage node to be charged and discharged; and a center node capacitively coupled to the storage node, the storage node surrounding the center node within the trench, the center node including a portion connecting to a gate of the transfer transistor to provide charge retention in the storage node during operation. ### Claim 11 (depends on 10) The trench capacitor cell as recited in claim 10, further comprising a bitline coupled to the transfer transistor for charging and discharging the trench capacitor. ### Claim 12 (depends on 10) The trench capacitor cell as recited in claim 10, wherein the gate of the transfer transistor includes a wordline. ### Claim 13 (depends on 12) The trench capacitor cell as recited in claim 12, wherein the wordline is an active wordline for the trench capacitor cell. ### Claim 14 (depends on 10) The trench capacitor cell as recited in claim 10, wherein the center node to the storage node capacitance is between about 0.5 fF to about 30 fF. ### Claim 15 (depends on 10) The trench capacitor cell as recited in claim 10, wherein the center node to the storage node capacitance is about 5fF. ### Claim 16 A trench capacitor cell comprising: a trench having an outer electrode formed in a substrate adjacent to the trench; a storage node formed in the trench and capacitively coupled to the outer electrode, the storage node being connected to a transfer transistor which enables the storage node to be charged and discharged; and a center node capacitively coupled to the storage node, the storage node surrounding the center node within the trench, the center node including a portion connecting to a passing wordline to provide charge retention in the storage node during operation. ### Claim 17 (depends on 16) The trench capacitor cell as recited in claim 16, wherein the transfer transistor includes a gate connected to an active wordline. ### Claim 18 (depends on 17) The trench capacitor cell as recited in claim 17, wherein the active wordline and the passing wordline are activated concurrently. ### Claim 19 (depends on 18) The trench capacitor cell as recited in claim 18, wherein the concurrent activation of the active wordline and the passing wordline is provided by disposing one bitline of each bitline pair on opposite sides of a sense amplifier such that the pair of bitlines are other than adjacently disposed. ### Claim 20 A trench capacitor cell comprising: a trench having an outer electrode formed in a substrate adjacent to the trench; a storage node formed in the trench and capacitively coupled to the outer electrode; a center node capacitively coupled to the storage node, the storage node surrounding the center node within the trench, the center node including a portion extending from the trench for connecting to a potential to provide charge retention in the storage node during operation, wherein the potential is a constant potential.